Widespread use of thermoelectric energy generation is limited both by low efficiency, and by the expense and toxicity of current thermoelectric materials (e.g. PbTe). Zintl compounds are a potential source of environmentally benign, inexpensive materials, due to the large variety of allowed chemical substitutions and the Earth-abundance of some of the most common constituents. There is a need in the art for Zintl compounds that can be used for thermoelectric energy generation.